Water heater with element in the top section - bad?

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Discussion Overview

The discussion revolves around the design of a 300 liter water heater with a single electrical heating element located in the top third of the tank. Participants are concerned about the implications of this design on water heating efficiency and temperature distribution, particularly whether the lower section of the tank will remain cold while the upper section is heated to the target temperature of 65°C.

Discussion Character

  • Debate/contested, Technical explanation

Main Points Raised

  • One participant expresses concern that the top-mounted element may lead to water segregation, resulting in only the upper third being heated.
  • Another participant notes that typical water heaters have both upper and lower elements, suggesting that the design in question is unusual.
  • A third participant describes their experience with water heaters that have both upper and lower elements, explaining the operational dynamics of such systems, including the role of thermostats and the sequence of heating.
  • There is a query about the model number of the heater to clarify its design features.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the design of the water heater. There are competing views regarding the typical configuration of heating elements in water heaters, with some asserting that having only one element is uncommon.

Contextual Notes

Participants reference operational characteristics of water heaters based on their experiences, but there is no detailed information provided about the specific model in question, which limits the discussion's scope.

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I've got a 300 liter water heater that has an electrical element (14 kW). The issue is that the element is positioned in the top third of the heater. I fear the water will become segregated so that only water in the top third will be heated, and the lower section will remain cold. The target temperature is 65°C and the entering water will be around 30°C. What do you think?
 
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I thought they typically had elements both in the top and bottom section. Do you have the model number?
 
russ_watters said:
I thought they typically had elements both in the top and bottom section. Do you have the model number?

I don't have it readily available, but I'm sure the only element is in the top section of the tank.
 
The water heaters I have dealt with have an upper and lower element. They are 4500 watts each and are never on at the same time. There is an upper and lower thermostat as well. Cold water enters the bottom and hot water is taken off the top. The lower thermostat will naturally be the first to come on. Typically if not a lot of water is used at one time it will be the only one that ever runs. If a lot of hot water is used then the bottom element will not keep up and when the top cools enough it will turn on and it will also switch the bottom one off. Never heard of a water heater with only one element unless it is a small 5 gallon heater.
 

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